air gets into bobcat engine fuel lines fuel system
Fuel Lines
How To

What Happens if Air Gets Into my Bobcat’s Fuel Lines?

The fuel lines in your machine's engine act as an important component in how your engine functions. (You can read more about the entire fuel system here.) Fuel lines can also be known as a hose or a pipe that is used to send fuel to each injector. I like to think of the fuel lines as the “middle man” between the high pressure fuel pump and the fuel injectors. Without a properly working fuel line, you may start to experience performance issues and more with your Bobcat. 

When referring to modern day fuel systems powered by diesel, it is a bit more rare for air to get sucked directly in by your fuel lines unless you are low on fuel supply or if you have a crack somewhere along your fuel lines which can be more serious. When air gets into fuel lines, air bubbles will start to form which can lead to stalling, idle, or no start in a Bobcat or any other similar machine. If you start to notice any of these symptoms you can perform the following test to dig deeper: 

Quick Test 

Before starting, make sure that your fuel tank is filled as being low on fuel can cause air to get in as mentioned above. To check if there is air in the fuel line, open the filler cap and turn on your engine. Let it run for a few minutes then turn it off and open the cap back up. If the engine is still running after a few minutes, it means that air is getting into the tank and is likely in your fuel lines. If your fuel tank is filled up then you can start to suspect that there is something going on within your fuel system. 

What Now? 

If you find that air is in fact getting into your fuel lines and it’s not related to your fuel tank being low, then there is a good chance that something else is going on within your fuel system/engine. We would then recommend you to check to see if your fuel pump and fuel filter have any issues such as a leak. If there is a leak in your fuel pump, then this can lead to air getting into your fuel lines. A leak in your gasket can also cause air to get into the system. 

You can start to think of your fuel system as a domino effect. In the case that a part such as your fuel filter, fuel pump, etc is showing issues that go beyond basic maintenance, it can very likely lead to issues with your fuel lines if the issue is not caught early on. 


Going back to the most important point we talk about in many of our guides, examples of air getting into your fuel lines is why regularly scheduled maintenance is so important in any heavy equipment machinery. Although diesel fuel systems such as Doosan’s system are modern and were designed to last longer than gasoline systems, these systems are also incredibly delicate and require more maintenance to prevent dirt, debris, air and more from getting in. If you schedule in frequent maintenance to change your fuel filter, drain water build-up, inspect your fuel pumps and so on every 6 months or every 250 hours you can spot problems early on before it wrecks your entire fuel system.